Narendra Modi, the Indian prime minister, will address a mass rally of Indian-Americans in Texas on Sunday, with a big-name guest alongside him – U.S. President Donald Trump.

The appearance of Trump at the "Howdy Modi!" rally has added to speculation that India and the United States could conclude a limited trade deal at the United Nations General Assembly (UNGA) in the coming days.

Trade deal close?

The trade deal under discussion would, sources told Reuters, lower some tariffs on U.S. produce and restore preferential treatment for some Indian exports to the United States.

Trump and Modi are scheduled to hold a bilateral meeting on Tuesday, the opening day of the UNGA, and the joint appearance at the 50,000-seat stadium in Houston on Sunday suggests a warming of ties after 18 months of high tension over trade relations.

The U.S. has taken issue with Indian investment rules on e-commerce that place limitations on outside companies, and Trump has complained about India's high tariff rates. Bilateral U.S. trade with India was worth 142 billion U.S. dollars in 2018.

There is also speculation that Trump will sign a deal with Japanese Prime Minister Shinzo Abe at the UNGA that lowers Japanese farm tariffs.

Why 'Howdy Modi' matters

Sunday's gathering in Texas is expected to be the largest-ever Modi event outside India, and the joint appearance with Trump is being presented as a major triumph for the Indian leader who just a few years earlier was banned from entering the United States.

Modi was denied a visa on religious freedom grounds in 2005, according to the Washington Post, and was effectively barred from traveling to the U.S. until his election as prime minister in 2014. 

The Indian prime minister has faced controversy since his reelection in 2019 over his move to revoke Kashmir's special status, an issue expected to be on the agenda at a UNGA session which will also be attended by Pakistani Prime Minister Imran Khan.

A trade deal would be a pre-election boost for Trump, meanwhile, and the rally in Houston is also an opportunity to woo Indian-Americans in a state that leans Republican but is slowly trending towards the Democrats. 

There are around 3.2 million Indian-Americans living in the U.S., according to the BBC, and polling by the Asian American Legal Defense and Education Fund (AALDEF) suggested a strong majority voted for Hillary Clinton in the 2016 presidential election. 

AALDEF's reseach suggested that Trump was backed by just 18 percent of Asian-American voters and 14 percent of Indian-American voters in 2016.